| crc32.c (17651) | crc32.c (33904) |
|---|---|
| 1/* crc32.c -- compute the CRC-32 of a data stream | 1/* crc32.c -- compute the CRC-32 of a data stream |
| 2 * Copyright (C) 1995-1996 Mark Adler | 2 * Copyright (C) 1995-1998 Mark Adler |
| 3 * For conditions of distribution and use, see copyright notice in zlib.h 4 */ 5 | 3 * For conditions of distribution and use, see copyright notice in zlib.h 4 */ 5 |
| 6/* $Id: crc32.c,v 1.8 1996/01/30 21:59:10 me Exp $ */ | 6/* @(#) $Id$ */ |
| 7 8#include "zlib.h" 9 10#define local static 11 12#ifdef DYNAMIC_CRC_TABLE 13 14local int crc_table_empty = 1; --- 25 unchanged lines hidden (view full) --- 40 combinations of CRC register values and incoming bytes. 41*/ 42local void make_crc_table() 43{ 44 uLong c; 45 int n, k; 46 uLong poly; /* polynomial exclusive-or pattern */ 47 /* terms of polynomial defining this crc (except x^32): */ | 7 8#include "zlib.h" 9 10#define local static 11 12#ifdef DYNAMIC_CRC_TABLE 13 14local int crc_table_empty = 1; --- 25 unchanged lines hidden (view full) --- 40 combinations of CRC register values and incoming bytes. 41*/ 42local void make_crc_table() 43{ 44 uLong c; 45 int n, k; 46 uLong poly; /* polynomial exclusive-or pattern */ 47 /* terms of polynomial defining this crc (except x^32): */ |
| 48 static Byte p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26}; | 48 static const Byte p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26}; |
| 49 50 /* make exclusive-or pattern from polynomial (0xedb88320L) */ 51 poly = 0L; 52 for (n = 0; n < sizeof(p)/sizeof(Byte); n++) 53 poly |= 1L << (31 - p[n]); 54 55 for (n = 0; n < 256; n++) 56 { 57 c = (uLong)n; 58 for (k = 0; k < 8; k++) 59 c = c & 1 ? poly ^ (c >> 1) : c >> 1; 60 crc_table[n] = c; 61 } 62 crc_table_empty = 0; 63} 64#else 65/* ======================================================================== 66 * Table of CRC-32's of all single-byte values (made by make_crc_table) 67 */ | 49 50 /* make exclusive-or pattern from polynomial (0xedb88320L) */ 51 poly = 0L; 52 for (n = 0; n < sizeof(p)/sizeof(Byte); n++) 53 poly |= 1L << (31 - p[n]); 54 55 for (n = 0; n < 256; n++) 56 { 57 c = (uLong)n; 58 for (k = 0; k < 8; k++) 59 c = c & 1 ? poly ^ (c >> 1) : c >> 1; 60 crc_table[n] = c; 61 } 62 crc_table_empty = 0; 63} 64#else 65/* ======================================================================== 66 * Table of CRC-32's of all single-byte values (made by make_crc_table) 67 */ |
| 68local uLongf crc_table[256] = { | 68local const uLongf crc_table[256] = { |
| 69 0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L, 70 0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L, 71 0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L, 72 0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL, 73 0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L, 74 0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L, 75 0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L, 76 0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL, --- 42 unchanged lines hidden (view full) --- 119 0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL, 120 0x2d02ef8dL 121}; 122#endif 123 124/* ========================================================================= 125 * This function can be used by asm versions of crc32() 126 */ | 69 0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L, 70 0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L, 71 0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L, 72 0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL, 73 0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L, 74 0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L, 75 0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L, 76 0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL, --- 42 unchanged lines hidden (view full) --- 119 0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL, 120 0x2d02ef8dL 121}; 122#endif 123 124/* ========================================================================= 125 * This function can be used by asm versions of crc32() 126 */ |
| 127uLongf *get_crc_table() | 127const uLongf * ZEXPORT get_crc_table() |
| 128{ 129#ifdef DYNAMIC_CRC_TABLE 130 if (crc_table_empty) make_crc_table(); 131#endif | 128{ 129#ifdef DYNAMIC_CRC_TABLE 130 if (crc_table_empty) make_crc_table(); 131#endif |
| 132 return (uLongf *)crc_table; | 132 return (const uLongf *)crc_table; |
| 133} 134 135/* ========================================================================= */ 136#define DO1(buf) crc = crc_table[((int)crc ^ (*buf++)) & 0xff] ^ (crc >> 8); 137#define DO2(buf) DO1(buf); DO1(buf); 138#define DO4(buf) DO2(buf); DO2(buf); 139#define DO8(buf) DO4(buf); DO4(buf); 140 141/* ========================================================================= */ | 133} 134 135/* ========================================================================= */ 136#define DO1(buf) crc = crc_table[((int)crc ^ (*buf++)) & 0xff] ^ (crc >> 8); 137#define DO2(buf) DO1(buf); DO1(buf); 138#define DO4(buf) DO2(buf); DO2(buf); 139#define DO8(buf) DO4(buf); DO4(buf); 140 141/* ========================================================================= */ |
| 142uLong crc32(crc, buf, len) | 142uLong ZEXPORT crc32(crc, buf, len) |
| 143 uLong crc; 144 const Bytef *buf; 145 uInt len; 146{ 147 if (buf == Z_NULL) return 0L; 148#ifdef DYNAMIC_CRC_TABLE 149 if (crc_table_empty) 150 make_crc_table(); --- 12 unchanged lines hidden --- | 143 uLong crc; 144 const Bytef *buf; 145 uInt len; 146{ 147 if (buf == Z_NULL) return 0L; 148#ifdef DYNAMIC_CRC_TABLE 149 if (crc_table_empty) 150 make_crc_table(); --- 12 unchanged lines hidden --- |